我一直在查看我的源代码,但无法弄清楚它有什么问题。我认为问题在于 Circle 类。当我从 DriverCircle 类调用变异器和访问器时,它给了我错误的输出。对于 getDiameter,它只是打印出 0。
public class Circle{
private double radius;
private double pi;
private double diameter;
private double circumference;
private double area;
public Circle(){
pi = Math.PI;
radius = 0;
}
public Circle(double radius){
this.radius = radius;
}
public void setDiameter(){
diameter = (2 * radius);
}
public double getDiameter(){
//diameter = 2 * radius;
return diameter;
}
public void setCircumference(){
circumference = (2 * pi * radius);
}
public double getCircumference(){
//circumference = 2 * pi * radius;
return circumference;
}
public double getArea(){
//area = pi * Math.pow(radius, 2);
return area;
}
public void setArea(){
area = (pi * Math.pow(radius, 2));
}
public void setRadius(double radius){
this.radius = radius;
}
public double getRadius(){
return radius;
}
public String toString(){
return "The radius is " + radius;
}
}
(测试者)...
import java.util.Scanner;
public class CircleDriver {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Please enter the radius: ");
Circle[] circles = new Circle[10];
Circle objectCircle = new Circle();
objectCircle.setRadius(input.nextDouble());
circles[1] = new Circle();
circles[2] = new Circle(2.0);
circles[3] = new Circle(3.5);
circles[4] = new Circle(5.0);
circles[5] = new Circle(0.0);
circles[6] = new Circle(15);
circles[7] = new Circle(25);
circles[8] = new Circle(-7);
circles[9] = new Circle(-10.0);
System.out.println("Initial call to toString():");
for (Circle c : circles)
{System.out.println("\t" + c);}
System.out.println("Call to getRadius (should be same as above):");
for (Circle r : circles)
{if (r != null)
{System.out.println("\t" + r.getRadius());}}
System.out.println("Call to getDiameter (should be twice the value shown above):");
for (Circle d : circles)
{if (d != null)
{System.out.println("\t" + d.getDiameter());}}
System.out.println("Calls to getCircumference:");
System.out.println("\tShould be 2 * PI: " + circles[1].getCircumference());
System.out.println("\tShould be 0.0: " + circles[5].getCircumference());
System.out.println("\nCall to getArea:");
System.out.println("\tShould be PI: " + circles[1].getArea());
System.out.println("\tShould be 0.0: " + circles[5].getArea());
System.out.println("Testing out the setRadius method:");
for (int i = 0; i < circles.length / 2; i++)
{if (circles[i] != null)
{circles[i].setRadius(i);}}
System.out.println("Call to toString after setting the first half of the objects:");
for (Circle c : circles)
{System.out.println("\t" + c);}
}
}